title: Melatonin and porphyrin in the harderian glands of the Syrian hamster: circadian patterns and response to autumnal conditions.
abstract: 1. Adult male Syrian hamsters were killed at nine intervals during a 24 hr period in the autumn, after 2 months either indoors in controlled conditions or in natural outdoor conditions. 2. Harderian glands were taken for determination of N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT) activities and melatonin and porphyrin concentrations. 3. Mean 24 hr Harderian NAT and melatonin values were lower outside than inside. 4. Twenty-four hour melatonin rhythms were detected with similar daytime (afternoon) acrophases in both environmental conditions. 5. An NAT rhythm was seen only in animals kept inside, with a circadian maximum in the late dark phase. 6. Mean 24 hr HIOMT activity was slightly higher outdoors than indoors, and 24 hr rhythms were not detected in either condition. 7. Mean porphyrin concentrations were higher outdoors, with 24 hr rhythms detected in both conditions and a significantly earlier nocturnal circadian maximum outdoors.
authors.affiliation: Department of Cellular & Structural Biology, University of Texas Health Science Center, San Antonio 78284.
authors.forename: G R
authors.initials: GR
authors.lastname: Buzzell
authors.forename: A
authors.initials: A
authors.lastname: Pangerl
authors.forename: B
authors.initials: B
authors.lastname: Pangerl
authors.forename: A
authors.initials: A
authors.lastname: Menendez-Pelaez
authors.forename: M K
authors.initials: MK
authors.lastname: Vaughan
authors.forename: J C
authors.initials: JC
authors.lastname: Little
authors.forename: S M
authors.initials: SM
authors.lastname: Hill
authors.forename: G M
authors.initials: GM
authors.lastname: Vaughan
authors.forename: R J
authors.initials: RJ
authors.lastname: Reiter
mesh_terms: D000121:Acetylserotonin O-Methyltransferase / Q000378:metabolism; D000123:Acetyltransferases / Q000378:metabolism; D000818:Animals; D002940:Circadian Rhythm; D006224:Cricetinae; D006243:Harderian Gland / Q000737:chemistry* / Q000201:enzymology / Q000502:physiology; D008297:Male; D008550:Melatonin / Q000032:analysis*; D008647:Mesocricetus; D011166:Porphyrins / Q000032:analysis*; D012621:Seasons
chemical_list: D011166:Porphyrins; D000121:Acetylserotonin O-Methyltransferase; D000123:Acetyltransferases; D008550:Melatonin